1. Field of the Invention
The present invention relates to an image-taking apparatus having an image-pickup device which photoelectrically converts an object image.
2. Description of Related Art
Conventionally, an electronic camera is generally known which photoelectrically converts an object image incident on an image-pickup device such as a CCD, etc., from an image taking lens, and A/D converts and records the photoelectrically converted image signal on a recording medium, and further displays the image on a built-in liquid crystal monitor. Recently, this type of electronic camera, in which the lens barrel is interchangeable, has been widely used.
In this type of electronic camera, as in the case of a conventional silver halide film camera, small size, excellent operability, and high-speed continuous shooting have been demanded. In an electronic camera, image data is temporarily stored in a buffer memory (volatile memory), and then transferred and recorded on a recording medium, such as a memory card, that is loadable to and unloadable from the camera main body. Therefore, in comparison with a silver halide film camera, a large-sized electrical circuit using a number of electrical parts including an imaging circuit, an image processing circuit, and an image display circuit, etc., is installed inside the camera.
Particularly, in an electronic camera including a detachable lens barrel, it is required that the taken image has high image quality and the luminance range of the taken image is broad. Therefore, employment of a large pixel number and a high-sensitivity image-pickup device is required. Accordingly, an image-pickup device whose imaging area is large is used, and in response to this, the area of a circuit board to which the image-pickup device is connected is also increased. Therefore, it is difficult to arrange a plurality of circuit boards, to downsize the camera, and to improve the operability.
FIG. 6 and FIG. 7 show a conventional example (refer to Japanese Patent Application Laid-Open No. 2002-135631) of an electronic camera including a detachable lens barrel. In these drawings, Reference numeral 101 denotes a camera body, in which a battery 102 is disposed inside a grip portion 101a projecting forward.
Reference numeral 103 denotes a lens barrel detachably attached to a mount portion 105a provided on the front face of the camera, which retains an image taking lens 104. Reference numeral 105 denotes a minor box, and inside the minor box 105, a quick return minor 106 which guides light that has passed through the image taking lens 104 to a finder optical system is provided, and behind the quick return minor 106, a focal plane shutter 107 is provided. Reference numeral 108 denotes a penta-prism, and reference numeral 109 denotes a finder optical system for observing an object image.
Reference numeral 110 denotes a front chassis, which retains the minor box 105. Reference numeral 111 denotes a rear chassis, which is joined to the front chassis 110 by screws, etc. The entire camera is increased in mechanical strength by joining these chassis 110 and 111.
Reference numeral 112 denotes an image-pickup device which is disposed behind the focal plane shutter 107 and has an imaging plane perpendicular to an optical axis Lo, and an imaging circuit board 113 to which the image-pickup device 112 is connected is disposed in parallel to the imaging plane of the image-pickup device 112 as shown in the figures.
Behind the imaging circuit board 113, a first circuit board 114 is disposed, and ahead of the imaging circuit board 113, a second circuit board 115 and a third circuit board 116 are disposed. In the first circuit board 114, for example, a mechanism driving control circuit, an image processing circuit, and an image display circuit, etc., are installed.
In the second circuit board 115, a power supply circuit is installed, and in the third circuit board 116, a strobe circuit, etc., are installed.
Further behind the first circuit board 114, an illumination light source 117 and a liquid crystal display section 118 are disposed. Reference numeral 119 denotes a housing part in which a memory card as an external recording medium and a card connector are set, and the housing part is provided along the first circuit board 114 in a region between the first circuit board 114 and the battery 102.
In the above-described electronic camera, since the imaging circuit board 113 to which the image-pickup device 112 is connected, the first circuit board 114, the second circuit board 115, and the third circuit board 116 are disposed close to each other between the front chassis 110 and the rear chassis 111, in particular, an electromagnetic wave generated from the power supply circuit in the second circuit board 115 and the boost transformer of the flash circuit in the third circuit board 116 become noise and influence the circuits on other circuit boards.
Furthermore, since the front chassis 110 and the rear chassis 111 are installed, the thickness of the entire camera is increased. As a result, the camera is increased in size, and it becomes difficult to stably hold the camera when taking an image.